1. Field of the Invention
The present invention relates generally to antennas, and more specifically to a strengthening means for a dipole whip antenna.
2. Description of the Related Art
The physical size of an antenna largely depends upon the purpose for which it is to be employed. For example, an antenna for receiving a particular frequency range must have an electrical length capable of resonating within that range to achieve optimum reception. Generally, lower frequencies require longer lengths because the wavelengths at lower frequencies are longer, but limitations in use often demand design modifications to achieve appropriate electrical length in a smaller space. It is known for antennas in some applications on mobile vehicles to be 10 feet or more in length.
Most such antennas are known as “whip” antennas because they have a thin, dielectric, flexible core that carries the electrical radiator and that is mounted to a vehicle by way of a spring. These types of antennas are known as “whip” antennas because the flexible core and spring together absorb energy from forces acting on the antenna, such as impacts. A typical core will be fiberglass. If a whip antenna were to impact an object while the vehicle is in motion, the flexible dielectric core and/or the spring can absorb the force of the impact, preventing damage to the antenna or its mounting.
Some antenna applications, however, are complex, requiring multiple frequency bands and electrical lengths that make the use of thin flexible whip antennas impractical. Such antennas may require hollow dielectric cores with diameters of 1 inch or more at a length of 10 feet, and consequently are more rigid. Impacts on such antennas tend to transfer forces to components within the hollow core such as feed lines and junctions, which may become dislodged and unable to function.